Iranian author Marjane Satrapi's acclaimed graphic memoir Persepolis has been removed from classrooms in Chicago in a move which has been condemned as "Orwellian".

Chicago schools reported on 15 March that they had been told by the district to remove the comic-strip memoir about growing up in Iran during the Islamic revolution from both libraries and classrooms. Widespread criticism and protests followed, and Chicago Public Schools (CPS) later backtracked on the move, saying that the memoir was only to be removed from seventh grade classrooms (equivalent to the second year of secondary school in the UK), and not from libraries, because "it contains graphic language and images that are not appropriate for general use in the seventh grade curriculum".

"We are also considering whether the book should be included, after appropriate teacher training, in the curriculum of eighth through tenth grades," said Barbara Byrd-Bennett, CPS chief executive, in a letter to principals.

"We want to make sure that the message about inhumanity [is what] kids walk away with, not the images of someone with exposed body parts urinating on someone's back or someone's being tortured. We are not protesting the value of this book as a work of art. We just want to make sure that when we put this book into the hands of students, they have the background, the maturity to appreciate the book," CPS office of teaching and learning chief Annette Gurley explained to Publishers Weekly.

But Chicago Teachers Union spokesperson Stephanie Gadlin dismissed the backtracking as "Orwellian doublespeak", pointing out that "unfortunately 160 elementary schools don't have libraries – and they know that". CTU's financial secretary Kristine Mayle added that "the only place we've heard of this book being banned is in Iran".

"We understand why the district would be afraid of a book like this – at a time when they are closing schools – because it's about questioning authority, class structures, racism and gender issues," said Mayle. "There's even a part in the book where they are talking about blocking access to education. So we can see why the school district would be alarmed about students learning about these principles."

A letter to Byrd-Bennett and members of the Chicago board of education from a host of free-speech organisations called the restriction on access to the book for junior high school students "extremely troubling", and said that removing the book because of objections to its content was "impermissible under the First Amendment".

"The title character of Satrapi's book is herself the age of junior high-school students, and her description of her real-life experiences might well have special relevance to them," states the letter from the National Coalition Against Censorship, the Comic Book Legal Defence Fund, American Booksellers Foundation for Free Expression, Association of American Publishers, the PEN America Centre and the National Council of Teachers of English. "The vast majority of Chicago middle school students are surely aware of the reality of violence and its devastating effects on people of all ages. Most have witnessed it on the news, if not in their own neighbourhoods."

"The district still has offered no satisfactory explanation as to why, all of a sudden and without any formal procedure, this book was suddenly and urgently targeted for removal and restriction," said Joan Bertin, NCAC executive director. "The book is highly regarded by educators and has been taught successfully in schools in Chicago and around the country. In our view, the decision is both pedagogically unsound and constitutionally suspect."

Satrapi herself, speaking to the Chicago Tribune, said the restriction was "shameful", and dismissed the CPS's concerns about what it had described as "powerful images of torture".

"These are not photos of torture … seventh graders have brains and they see all kinds of things on cinema and the internet. It's a black-and-white drawing and I'm not showing something extremely horrible. That's a false argument. They have to give a better explanation," said Satrapi.